Central Basin Groundwater Replenishment"Surface spreading" is the primary method the WRD uses to replenish the Central groundwater basin. This occurs when water is directed and placed at the Rio Hondo and San Gabriel Coastal Spreading Grounds. Owned and operated by the Los Angeles County Department of Public Works (LADPW), the spreading grounds are situated over a geologic uplift that allows water to percolate from the surface of the ground into the water-bearing aquifers below ground.
WRD coordinates regular meetings with LADPW, the Metropolitan Water District of Southern California, County Sanitation District of Los Angeles County, and other water interests to discuss replenishment water availability, spreading grounds operations, scheduling of replenishment deliveries, upcoming maintenance activities, and facility outages or shutdowns. The WRD tracks groundwater levels in the Montebello Forebay, a hydrogeologic area that contains the spreading grounds, weekly to assess general basin conditions and determine the level of artificial replenishment needed. The WRD also monitors the amount of recycled water used at the spreading grounds to maximize use and complying with regulatory guidelines. |
The WRD actively monitors operation and maintenance practices at the spreading grounds in order to ensure optimum replenishment opportunities. A combination of local stormwater runoff flow, recycled water, and imported water is used to meet replenishment demands. Stormwater is free and the District looks for ways to increase the use of local stormwater from the San Gabriel and Los Angeles river systems in order to minimize the purchase of costly replenishment water.